1. Field of the Invention
The present invention relates generally to a manufacturing method of a heat pipe structure, and more particularly to a thinner heat pipe structure manufactured at lower cost and a manufacturing method of the heat pipe structure.
2. Description of the Related Art
A heat pipe has heat conductivity several times to several tens times that of copper, aluminum or the like. Therefore, the heat pipe has excellent performance and serves as a cooling component applied to various electronic devices. As to the configuration, the conventional heat pipes can be classified into heat pipes in the form of circular tubes and heat pipes in the form of flat plates. For cooling an electronic component such as a CPU, preferably a flat-plate heat pipe or thin heat pipe is used in view of easy installation and larger contact area. To catch up the trend toward miniaturization of cooling mechanism, the heat pipe has become thinner and thinner in adaptation to the cooling mechanism.
The heat pipe is formed with an internal space (chamber) as a flow path for the working fluid contained in the heat pipe. The working fluid is converted between liquid phase and vapor phase through evaporation and condensation and is transferable within the heat pipe for transferring heat. The heat pipe is formed with a sealed void (chamber) in which the working fluid is contained.
The heat pipe is used as a remote end heat conduction member. The heat pipe is fitted through a radiating fin assembly. The working fluid with low boiling point is filled in the heat pipe. The working fluid absorbs heat from a heat-generating electronic component (at the evaporation end) and evaporates into vapor. The vapor working fluid goes to the radiating fin assembly and transfers the heat to the radiating fin assembly (at the condensation end). A cooling fan then carries away the heat to dissipate the heat generated by the electronic component.
The heat pipe is manufactured in such a manner that metal powder is filled into a hollow tubular body by means of a mandrel of a tool. Then the metal powder is sintered to form a capillary structure layer on the inner wall face of the tubular body. Then the tubular body is vacuumed and filled with the working fluid and then sealed. Alternatively, a mesh capillary structure body is placed into a tubular body and sintered to form a capillary structure layer on the inner wall face of the tubular body. Then the tubular body is vacuumed and filled with the working fluid and then sealed. On the demand of the electronic equipment for slim configuration, the heat pipe must be made with the form of a thin plate.
In the conventional technique, the heat pipe is flattened into a flat-plate form to meet the requirement of thinning. After the metal powder is filled into the tubular body and sintered, the tubular body is flattened into a flat plate. Then the flat plate is filled with the working fluid and finally sealed. Alternatively, the tubular body is first flattened into a flat plate. Then the metal powder is filled into the tubular body and sintered. However, after flattened, the internal chamber of the flat plate is extremely narrow. Under such circumstance, it is quite hard to fill the metal powder into the chamber. Moreover, the capillary structure in the heat pipe must provide both support force and capillary attraction for the heat pipe. In such a narrow space, the effect provided by the capillary structure is limited.
Furthermore, the vapor passage inside the heat pipe is so narrow that the vapor-liquid circulation is affected.
According to the above, the conventional technique has the following shortcomings:
1. It is quite hard to process the thin heat pipe.
2. The capillary structure in the heat pipe is likely to be damaged.
3. The manufacturing cost of the thin heat pipe is relatively high.